Hey fellas...I need some input on this issue I experienced today. The car was fine yesterday. Anyhow...

The car feels like it's bouncing/shaking up and down very fast whenever I'm cruising 50mph+ like I'm driving over uneven pavement. The shaking stops when I let off the gas, and will resume within a few minutes after I step on the gas again (to maintain speed, go up inclines, etc). It shakes harder the faster I go, but will stop instantly when I let off.

I have new tires with less than 5k on them, and they're balanced. All the lug nuts are tightened to spec.

Anyone got any ideas what's causing the shake?

 

Front end alignment? That's my best guess.

 

Alignment/balance.

 

I had the alignment was done about a month ago, the steering is perfectly straight. The problem goes away as soon as I let off the gas.

 

Check the shafts coming out of each side of the transmission that turn the front wheels. I don't know what they're called on a front wheel drive car. On my jeep they were U-joints. I had one go bad and it did what you're describing.

 

Sounds like alignment and I agree with the other people too. Also check the axles also......be cautious man. That's all I can say besides taking it to the dealership or something.

 

Do you have the RSA's on still

 

maybe a bent rim

 

this doesn't sound like a bent rim or balance or anything of the sorts. It sounds like something with the transmission. I would be very careful.

 

also check your motor mounts I've seen this on 6th gen

 

hopefully its something minor like low on power steering fluid
otherwise it could be something suspension wise, lose bolt on a control arm, etc

 

Sounds like u either have a bad cv axle or bad motor mounts,also make sure u dont have a shifted belt on one of your tires,I doubt its the tires because it only does it under acceleration but ive seen crazier things on cars in the last twenty seven years since i started working on them........

 

Ascendant...any updates on this?

 

almost forgot i had this thread going.

but i took it to the mechanic shop, and we can't replicate the problem for some odd reason. the mechanic did a visual inspection of the car off the ground, he didn't spot anything out of the norm. so he told me to bring it back when i feel the vibrations again...

but then it came back the next day as i was driving to my clinical site. after work, i took it to discount tire to see if it needed to be rebalanced. well, turns out 3 of my rims are bent. one of the techs there took me out to the bays to show me how my wheel was wobbly when the balancing machine spun the tire.

he said its common for alloy wheels to get out of shape after 4-5 years of driving...and houston's streets aren't always that nice. any truth to the tech's statement?

 

Well, were they bent? lol

 

Are these factory wheels? If so, I'm extremely shocked...I've never heard anything like that tech's statement?

 

yeah factory wheels.

but hell, why would the shaking happen suddenly? i fig if the wheels are bents, i would have experienced these symptoms long ago...

 

When you get your wheels balanced, are you getting a road force balance? If so, does the person doing the balancing actually know how to use the machine properly (you'd be surprised how many techs have no idea what the machine can actually do)? Have you hit any decent potholes recently? Rotated the tires recently?

What doesn't make sense is that it only does it when you are accelerating. I had a vibration issue, but it was constant at speeds over 55mph...ended up with a road force balance and it went away. If it was a tire/rim issue, I would think you would have the problem constantly...whether accelerating or not. I'm leaning towards a transmission/transaxle issue.

 

little update:

this was the culprit that's causing the vibrations...


passenger side


driver side

car is still at the shop waiting for repairs.

 

Is this what it looked like after they started working on it, or is this what it looked like just from driving it? If this is how it looked when you got to the mechanic, then I would take one of the transaxles and smack whichever mechanic you went to that did a "visual" inspection and didn't find anything. I did a brake job for a co-worker, and as soon as I pulled the tire off, I noticed grease was slung all over the tie rod end and lower control arm. I IMMEDIATELY started looking for the culprit. It didn't take long to find the CV boot was leaking. This is not something that any mechanic should have missed...unless they are blind.

You are very lucky that the passenger axle didn't seperate...that would have been a whole new set of problems. I'm glad somebody finally found the problem and is repairing it.

 

So about how much did that run you?Having that issue right now

 

I have a shaking issue on the freeway but it's not dependent on the gas pedal. It does it at certain speeds and more so if I start to apply the brakes. Could that be the struts or the alignment?

 

If your car not pulling left/right under acceleration then I personally would rule out alignment issues.vibrating under brakin could be warped rotors or control arm.

 

Dam how in the world does this happen?

 

dammn that looks bad, hopefully you get it fixed soon.

 

What I don't see is the grease splattered all over? If it was leaking that badly, and oozing as in the pictures, the constant rotation would have caused it to spray.

I hope you trust your mechanic..

 

When my boot let go it sprayed ALLLLL over underneath. I had to use this stuff, I think its called, Purple Magic grease remover from Lowes. I had to spray everything down with it and then rinse it down and it came out great.

 

I have the same problem. A hole in my CV boot